In recent years, a relatively inexpensive method of manufacturing a silicon carbide (SiC) substrate with excellent heat resistance and withstand voltage in comparison to existing silicon (Si) substrate has been established.
Processes using the SiC substrate include implanting aluminum ions as a dopant, in which an ion implantation apparatus having an ion source that generates an aluminum ion beam is used.
With such an ion source, methods of generating aluminum ions include reacting aluminum nitride or alumina, which is disposed in a container, with a fluorine-based gas (for example, PF3) introduced into the container.
However, during the reaction of aluminum nitride with PF3, there is an disadvantage that aluminum fluoride (AlFx) is produced as a byproduct. The aluminum fluoride adheres to a low-temperature face of an inner space of a gas introduction pipe. Specifically, the aluminum fluoride adheres to the supply-side leading end and the interior wall face of a gas supply pipe, clogging the gas supply pipe.
Accordingly, the conventional method of generating aluminum ions has had a problem that requires frequent maintenance of the ion source.